Combined air and water heaters



Feb. 22, 1966 J. H. EUBANKS COMBINED AIR AND WATER HEATERS 4Sheets-Sheet 1 Filed May 28, 1963 INVENTOR Joseph H. Eubanks ATTORNEYJFeb; 22, 1966 J, EUBANKS 3,236,226

COMBINED AIR AND WATER HEATERS Filed May 28, 1963 4 Sheets-Sheet 2INVENTOR Joseph H. E ubanks ATTORNEYS J. H. EUBANKS 3,236,226

COMBINED AIR AND WATER HEATERS 4 Sheets-Sheet 5 Feb. 22, 1966 Filed May28, 1963 INVENTOR Joseph H. Eubanks BY M? y% ATTORNEYS Feb. 22, 1966 J.H. EUBANKS COMBINED AIR AND WATER HEATERS 4 Sheets-Sheet 4 Filed May 28,1963 INVENTOR Joseph h. Eubanks M%6w4 ATTORNEYS United States Patent3,236,226 COMBINED AIR AND WATER HEATERS Joseph H. Eubanlrs, SchuylkillHaven, Pa., assignor to Thermodynamics, Schuylkill Haven, Pa., acorporation of Pennsylvania Filed May 28, 1963, Ser. No. 283,762 3Claims. (Cl. 126101) This invention relates to heating systems and moreparticularly to combined heating systems for supplying from a singlesource the warm air or water required for space heating and the hotwater required for the usual domestic purposes.

While the advantages of combining a furnace and a domestic hot waterheater have long been recognized, separate units continue to dominatethe market because of the failure of prior proposals to provide anefficient, compact, flexible and inexpensive combined unit.

In many cases the cost of the combined unit has exceeded the total costof the conventional separate units. Also, in most cases the combinedunits were not able to supply efficiently the widely varyingrequirements for warm air and hot water and to accommodate the change inrequirements between summer and winter operation.

It is, accordingly, a principal purpose and object of the presentinvention to provide improved combined air and water heaters whichovercome these deficiencies of prior units and which olfer increasedefficiency and flexibility of operation and yet which are compact and ofsimplified, durable construction and which can be manufacture d, soldand operated at reduced cost.

It is a further object of the present invention to provide improvedcombined air and water heaters which because of their uniqueconstruction eliminate extreme temperature diiferentials throughout thesystem thus increasing their service life and increasing theirefliciency.

It is also an object of the present invention to provide improvedcombined air and water heating units which are unusually compact and maythus be installed in a variety of locations within a dwelling.

It is a further object of the present invention'to provide improvedcombined air and water heaters which have an unusual degree offlexibility of operation and which accordingly can be utilized tosatisfy all of the requirements for heating systems having widelydiffering configurations. For example, the novel units herein disclosedmay be used in a system in which a portion of the dwelling is heated byforced hot air and the remainder is heated by hot water supplied toconventional radiators or to baseboard heaters or the like.

Additional objects and advantages will become apparent as thedescription proceeds in connection with the accompanying drawings inwhich:

FIGURE 1 is a side view of the combined air and water heater unit of thepresent invention with parts broken away to show interior details;

FIGURE 2 is a top plan view of the unit;

v FIGURE 3 is a front view of the unit of FIGURE 1;

FIGURE 4 is a rear view with parts broken away to show interior details;and

FIGURE 5 is an enlarged fragmentary section of one of the combined heatexchanger assemblies employed in the unit.

Referring now more particularly to the drawings, the main heat exchangeportion of the combined air-water heater of the present invention isenclosed in a housing 20 of sheet metal construction formed by a bottomwall 21, and side walls 23 and 24 welded or otherwise suitably securedtogether.

The ends of the housing 20 are formed by a pair of headers, 25 and 26which extend over the full width and ice height of the housing and arewelded to the bottom wall 21. The header 25 comprises inner and outerwalls 27 and 28, top wall 29 and side walls 30 and 31 which formextensions of the housing side walls 23 and 24, the walls preferablybeing welded to form a water tight structure. The header 26 is ofsimilar construction and includes inner and outer walls 32 and 33, a topwall 34 and side walls 35 and 36.

Secured to the lower port-ion of end wall 33 of the header 26 is acombustion unit 37 which, in the present. instance is an oil burner. Aflue collector 38 leading to a smoke pipe 39 is also mounted on the wall33 above the oil burner 37. The side wall 24 of the housing has a lowershrouded opening 40 for connection to the outlet scroll of a fan 42driven by -a motor 43, the fan and motor being mounted in a housing 44extending vertically in side-by-side relation with the housing 20. Theupper end of the fan housing is connected to the conventional return airducts (not shown) through an opening 46. The usual replaceable filter 48is positioned in the housing 44 in the path of the incoming air. The topof the main housing 20 is provided with a central open-ing 50 forconnection to the warm air delivery ducts (not shown) which lead to theseveral rooms of the dwelling. The air delivered by the fan 42 passesthrough the opening 40 and around a combustion tube 52 then upwardlyacross the heat exchange apparatus to be described, through arectangular passage formed by the side walls 23 and 24 and inner wallsof the headers 25 and 26.

The combustion tube 52, which is cylindrical, is welded at one end tothe header wall 32 in surrounding relation with an intermediate tube 55which extends through header 26 and connects the burner 37 to theinterior of the combustion tube 52 and is welded to the header walls 32and 33. The opposite end of the combustion tube 52 extends throughheader 25 and is welded to the header walls 27 and 28.

The combustion tube 52 opens into a collector chamber or gas reversalchamber 58 formed by a rectangular sheet metal structure 59 welded tothe outer header wall 28. The gas reversal chamber is closed by a cover60 detachably secured by clamps 62 to the sheet metal annulus 59. Thecover 60 is preferably lined or filled with an insulating refractorymaterial.

The principal heat exchange area within the heater of the presentinvention is provided by a series of identical fire tube, water tubeassemblies, each of which is indicated generally at 64. As best shown inFIGURE 5, each of these assemblies comprises an inner fire tube 66, theopposite ends of which are supported by and welded to the header walls28 and 33, respectively. Thus, these fire tubes 66 connect the gasreversal chamber 58 with the collector 38 to provide a path for the hotcombustion products produced by the burner 37. The fire tubes 66 aresurrounded by water tubes 68, the opposite ends of which are supportedby and welded to the inner header walls 27 and 32. Thus, the annularspaces between the water tubes 68 and the fire tubes 66 provide a seriesof paths for connecting the two water filled headers 25 and 26. It willbe noted that the heat exchanger assemblies 64 are each inclinedslightly to promote convection flow from right to left as viewed inFIGURE 1. The headers 25 and 26 are also connected by lower and upperconduits 69 and 71.

To increase the heat exchange capacity of the units 64, they areprovided with a series of thin sheet metal rectangular fins 70 which arepress fitted onto the outer periphery of the water tubes 68. The finsare of rectangular configuration and are so dimensioned that they occupysubstantially the entire air passage above the combustion tube 52.

The supply of domestic hot water is obtained by an immersion coil 72which extends substantially entirely across the header 26. The immersioncoil is provided with the usual inlet and outlet connections 74 and 76,respectively, for connection to the hot water lines of the dwelling.While the immersion heater is shown positioned at the upper end of theheader 26, it may also be mounted between the tube 55 and the lowermostof the heat exchanger assemblies 64 or may be mounted below the tube 55,depending on the requirements of the particular installation involved.

To assure maximum efficiency of operation and to provide sufiicient hotwater or suificient hot air without excessive heating of the air or ofthe water, separate controls are provided for the burner 37 and the fan42. More specifically, the burner 37 is controlled solely in response tothe temperature of the water, preferably sensed by an aquastat which ispositioned in the header 26 adjacent the immersion coil 72. Theoperation of the fan 42, on the other hand, is controlled by a roomthermostat positioned in the usual location in the dwelling.Accordingly, the volume of water filling both the headers and the heatexchange unit 64 is constantly maintained at or very close to apredetermined temperature which is sufiicient to satisfy the demand forhot water or for hot air up to the rated capacity of the unit. When theroom thermostat calls for additional heat the fan 42 is put intooperation to cause the air to circulate over the fins 70, the watertubes 68, and the inner surfaces of the headers 25 and 26. The totalarea of these heat exchange surfaces is more than adequate to heat theair thus circulated to the required temperature. The temperature of thewater required to produce the desired air temperature is entirelycompatible with the temperature required to satisfy the needs fordomestic hot water.

The temperature of the heated reservoir of the water will be reducedwhenever the fan 42 operates or when domestic water is used. Under thesecircumstances the burner will operate to restore the heat level of thewater in the two headers.

Because of the substantially constant temperature of the components, thedeterioration which occurs in the usual warm air furnace in summer isentirely eliminated. Also extreme temperature differentials, which areunavoidably encountered in the usual warm air furnace, are eliminatedbecause of the water backing of the surfaces which are exposed to thehighest temperatures.

The entire unit is unusually compact. For example, a unit having a100,000 B.t.u. capacity, which is suflicient for the normal threebedroom house, is only 30 inches high and about 40 inches long. Withinthis relatively small envelope the capacity can be varied as desired byadding or deleting one or more of the heat exchange assemblies 64.

Because of the relatively large reservoir of heated water, this watercan be used for space heating as well as for heating water for domesticrequirements. For example, in one level houses of the ranch type, theruns of the warm air ducts are so long that it is difiicult to insure anadequate supply of warm air to rooms which are remote from the heatingunit. In such a case these difficult to heat rooms can be served by ahot water system, for example, radiant baseboard heating or a fullradiant system. Thus the unit can be tailored exactly to meet unusual aswell as conventional requirements with little or no added cost.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

l. A combined air and Water heater comprising a housing havingessentially vertical side walls and end walls and an essentiallyhorizontal top Wall, means forming Water filled headers extending thefull Width and height of said end walls inwardly thereof, the innerwalls of said headers and said side walls forming an air passageconnecting an opening in one of said side walls and an opening in saidtop wall, a burner carried by one of said end walls for supplying heatedcombustion products, means forming a gas reversal chamber adjacent theopposite end wall, a combustion tube assembly extending through each ofsaid headers and across said air passage connecting said burner and saidgas reversal chamber, a fan for forcing air through said passage andover a portion of said combustion tube assembly, a plurality of heatexchangers extending across said air passage between said headers, saidheat exchangers each having a water tube connecting the interior of oneheader to the interior of the other header, and each heat exchangerhaving a fire tube extending through said headers through which thecombustion products pass from said gas reversal chamber to a smoke pipe.

2. A combined air and water heater comprising a housing havingessentially vertical side walls and end walls and an essentiallyhorizontal top wall, means forming water filled headers extending thefull width and height of said end walls inwardly thereof, the innerwalls of said headers and said side walls forming an air passageconnecting an opening in one of said side Walls and an opening in saidtop wall, a burner carried by one of said end walls for supplying heatedcombustion products, means forming a gas reversal chamber adjacent theopposite end wall, a combustion tube assembly extending through saidheaders and across said air passage connecting said burner and said gasreversal chamber, a fan for forcing air through said passage and over aportion of said combustion tube assembly, a plurality of heat exchangersextending across said air passage between said headers, said heatexchangers having a water tube connecting the interior of one header tothe interior of the other header and each heat exchanger having a firetube extending through said Water tube concentrically thereof andextending through said headers into said gas reversal chamber, thecombustion products passing through said fire tube from said gasreversal chamber to a smoke pipe, and a plurality of fins carried by theouter surface of each of the said water tubes and substantially fillingsaid air passage.

3. A combined air and water heater comprising a hous ing having sidewalls, water filled headers extending the full width and height of saidhousing and forming the ends thereof, the inner walls of said headersand said side Walls forming an air passage, means forming a gas reversalchamber at the outer side of one of said heaters, a plurality of heatexchangers extending across said air passage between said headers, saidheat exchangers each having a water tube connecting the interior of oneheader to the interior of the other header, and each heat exchangerhaving a fire tube positioned within and extending through said Watertube and through said headers, one end of said fire tubes communicatingwith said gas reversal chamber and the other end of said fire tubescommunicating with a smoke pipe, a burner for supplying heatedcombustion products, a combustion tube assembly extending through eachof said headers and into said gas reversal chamber and connecting saidburner to said gas reversal chamber, a plurality of heat exchanger finscarried by said water tubes externally thereof, a fan for forcing airthrough said air passage over a portion of said combustion tube assemblyand over said heat exchanger fins and said water tubes.

(References 011 following page) 5 6 References Cited by the Examiner2,216,175 10/ 1940 Helbing.

2,533,508 12/1950 Riu 126101 UNITED STATES PATENTS 2,573,364 10/1951Scharif 1261()1 1,532,506 4/1925 McGregor 23718 2,786,634 3 1957 w n 1210 X 1,607,458 11/1926 Hocher 126101 2,006,849 7/ 1935 Warren 5 JAMES W.WESTHAVER, Primary Examiner.

2,026,031 12/1935 Gerspacher 126-101

1. A COMBINED AIR AND WATER HEATER COMPRISING A HOUSING HAVINGESSENTIALLY VERTICAL SIDE WALLS AND END WALLS AND AN ESSENTIALLYHORIZONTAL TOP WALL, MEANS FORMING WATER FILLED HEADERS EXTENDING THEFULL WIDTH AND HEIGHT OF SAID END WALLS INWARDLY THEREOF, THE INNERWALLS OF SAID HEADERS AND SAID SIDE WALLS FORMING AN AIR PASSAGECONNECTING AN OPENING IN ONE OF SAID SIDE WALLS AND AN OPENING IN SAIDTOP WALL, A BURNER CARRIED BY ONE OF SAID END WALLS FOR SUPPLYING HEATEDCOMBUSTION PRODUCTS, MEANS FORMING A GAS REVERSAL CHAMBER ADJACENT THEOPPOSITE END WALL, A COMBUSTION TUBE ASSEMBLY EXTENDING THROUGH EACH OFSAID HEADERS AND ACROSS SAID AIR PASSAGE CONNECTING SAID BURNER AND SAIDGAS REVERSAL CHAMBER, A FAN FOR FORCING AIR THROUGH SAID PASSAGE ANDOVER A PORTION OF SAID COMBUSTION TUBE ASSEMBLY, A PLURALITY OF HEATEXCHANGERS EXTENDING ACROSS SAID AIR PASSAGE BETWEEN SAID HEADERS, SAIDHEAT EXCHANGERS EACH HAVING A WATER TUBE CONNECTING THE INTERIOR OF ONEHEADER TO THE INTERIOR OF